An image processing apparatus comprises a heat roller configured to heat a sheet with heat generated by a plurality of heat generating elements and a controller configured to control a current supplied to the heat generating elements from an AC power supply. The controller controls a timing at which the current flows or does not flow to the heat generating elements according to a first set of control parameters, such that a total of a first sum of estimated absolute value magnitudes of a positive polarity current flowing to the heat generating elements during one duty cycle and a second sum of estimated absolute value magnitudes of a negative polarity current flowing to the heat generating elements during the one duty cycle, is lower when the heat generating elements are controlled according to the first set relative when the heat generating elements are controlled according to other sets.